SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c4df289c862ae241304ea9e1b66b1d999e4f3d96975062a5fcbe75030e64ba31' 
  AND token = 'CQ0uuXYt208oG745ZTw+jwjyuYDEm4UaI87R/hZuc9o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}